US 2015173671 A1 discloses a method and system of physiological monitoring. The method includes the steps of: measuring a quantity relating to a first subject with a first sensor positioned in or in proximity of the first subject and configured to provide a first signal, measuring a quantity relating to a second subject with a second sensor positioned in or in proximity of the second subject and configured to provide a second signal, and analyzing the first and the second signal and the interrelation of the first and second signal in order to determine at least one event relating to the first and/or the second subject.
EP 2976994 A2 discloses a sleep assist system to monitor and assist the user's sleep. The system comprises: a bedside device adapted to be positioned near the user's bed, the bedside device optionally comprising a loudspeaker, a light source, a microphone, a light sensor, a temperature sensor, a control unit, an air quality sensor, a display unit, a user interface. The system further comprises a first sensing unit positioned in the user's bed comprising one or more sensors adapted to sense at least pressure and changes in pressure exerted by the user lying in the bed. An additional sensor device is in contact with the user's body, and coupled to the bedside device. The system is configured to correlate the data obtained from both the first sensing unit and the additional sensor device.
Sleep is a critical part of our lives. It ensures that our bodies rest and can repair and is therefore crucial for long-term health. It is therefore important that people, i.e. subjects, sleep properly. Without proper sleep, chronic health issues may arise. For this reason, many solutions have been proposed that facilitate the monitoring of sleep by a subject, for example to diagnose sleep disorders or to improve the sleep process by creating an atmosphere in a confined space in which the subject is sleeping to improve the quality of sleep for that subject.
For example, CN 203101953 A discloses a device that comprises a brainwave detecting means to detect the brainwaves of a subject and a controller arranged to analyze these brainwaves to detect various sleep stages, with the device arranged to control an air conditioner, humidifier and/or lighting controller to improve the sleep of that subject in response to a detected sleep stage.
A drawback of this device is that it requires physical contact with the subject attempting to sleep. Similar solutions, e.g. solutions in which pressure sensors or the like are fitted to a mattress on which a subject is attempting to sleep, to an extent suffer from the same problem or may suffer from accuracy problems. This physical contact can be perceived as uncomfortable and as such cause a disruption of the sleep of the subject being monitored. Hence, there exists a need for a sleep monitoring system that can monitor sleep in a more unobtrusive manner. In particular, there exists a need for a sleep monitoring system that can accurately monitor sleep of a pair of subjects, e.g. a couple sharing a bed, in an unobtrusive manner.